Rheumatoid arthritis is a multisystemic inflammatory autoimmune diseases mainly involving bones and joints, and the disease also includes ankylosing spondylitis; the pathogenesis of the disease is unknown. Clinically, the most common inflammatory joint disease is rheumatoid arthritis, and ankylosing spondylitis is in the next place. They seriously affect patient's functional status, quality of life and life expectancy. Because of their chronicity feature, related complication and long-term dysfunction, they have huge influence on society and economy. Now, the main treatment for autoimmune diseases involving bones and joints including rheumatoid arthritis, ankylosing spondylitis etc. is medication (commonly used drugs are non-steroidal anti-inflammatory drugs, and newly-marketed biopreparate such as TNF-α inhibitor), but none of these drugs can completely control the development of patient's condition, and they have serious side effects. Therefore, there is an urgent need for developing new type of drug to treat autoimmune diseases involving bones and joints including rheumatoid arthritis, ankylosing spondylitis etc. One of R&D hot spots and directions is to search for active medicinal substance in Chinese herbs.
Gelsemium elegans Benth., a medicinal plant of a long history, is the whole plant of Loganiaceae plant Gelsemium elegans Benth, which abounds in Fujian, Zhejiang, Guangdong etc. of China. Gelsemium has various physiological and pharmacological activities, such as functions of anti-tumor, relaxing smooth muscle, suppressing platelet aggregation etc.; but it has stronger toxicity and is not suitable for direct use in medicine. The main active ingredient of Gelsemium is alkaloid, including more than 40 kinds of homologue monomers such as koumine, gelsemine and gelsenicine etc. Although the total alkaloidal toxicity of Gelsemium is high, the toxicity of each monomers is different. The koumine is an effective ingredient which has the highest content and less toxicity in domestic Gelsemium alkaloid monomers, which has a good prospect of development and application.
Koumine, with the molecular formula as C20H22N2O, has the following structural formula:

The main source of koumine is Gelsemium, from which the koumine can be extracted and separated, for example, by use of column chromatography, or of the method recited in the patent “The Method of Separating and Preparing Gelsemium Alkaloid Monomer from Gelsemium by High Speed Counter-Current Chromatography” invented by this inventor (granted, Patent No. CN101323618B), which provides a way to obtain koumine efficiently and quickly, and lays the foundation of industry application of koumine.
In more recent years, the researches on koumine are increasing. It is found that koumine has various physiological and pharmacological activities such as anti-tumor effect [Darong Wu, Rui Qin, Jing Cai, Debiao Chi. The research on anti-tumor effect of koumine, Pharmacology and Clinics of Chinese Materia Medica, 2006, 22 (5): 6-8], anti-anxiety effect (a China patent application has been filed: the application of gelsemine, koumine, gelsevirine in preparation of drugs for treating anxiety, patent No. ZL 201110130826.6), anti-chronic pain effect (a China patent application has been filed: the application of koumine as only active ingredient in preparation of drugs for treating chronic pains, patent No. ZL 200810071467.X) etc. However, the effect of koumine against autoimmune diseases including rheumatoid arthritis or the like and possible use thereof have not been reported in literatures and patents. This patent application discloses an effect of koumine against rheumatoid arthritis and an application of the koumine in preparation of drugs for treating autoimmune diseases involving bones and joints including rheumatoid arthritis, ankylosing spondylitis etc.